Semi-trailer trucks often include one or more fairing panels that extend downwardly from an area near the bottom of the cab or sleeper portion of the vehicle. These panels increase the aerodynamic efficiency of the vehicles, thereby improving fuel economy and reducing operating costs. The panels also improve the aesthetics of the vehicles by concealing vehicle components, such as fuel tanks, fluid lines, frame components, etc., that would otherwise be visible.
FIG. 1 shows a typical fairing under-cab installation for a known semi-trailer truck. The vehicle 10 includes a chassis frame 12 supported by a plurality of wheels 14. A cab 16 is located on a forward end of the frame 12 to provide a vehicle operator with an enclosure from which to operate the vehicle 10. An optional sleeper 18 extends from a rear portion of the cab 16 to provide sleeping quarters and a living space for the vehicle operator. A fairing panel 20 is mounted to the vehicle frame 12 to extend downwardly from an area just below the cab 16 and the sleeper 18.
The cab 16 and the sleeper 18 are mounted to the frame 12 with a suspension in order to provide a smoother ride for the vehicle operator. As a result, relative motion necessarily occurs between the cab 16 and the frame 12 and between the sleeper 18 and the frame 12 during vehicle operation. Because the fairing panel 20 is mounted to the frame 12, relative motion also occurs between the cab 16 and the fairing panel 20 and between the sleeper 18 and the fairing panel 20. To accommodate this relative motion, the fairing panel 20 is mounted to the frame 12 so that a gap 22 exists between the fairing panel 20 and the cab 16 and between the fairing panel 20 and the sleeper 18. The gap 22 allows the cab 16 and the sleeper 18 to move relative to the frame 12, and thus the fairing panel 20, during vehicle operation. This in turn prevents unwanted contact between the fairing panel 20 and the cab 16 and/or sleeper 18.
While the above-described fairing system provides improved aerodynamic efficiency and improved vehicle aesthetics, the gap between the fairing panel and the cab and sleeper causes undesirable aerodynamic drag. Further, the gap allows structure that would ideally be concealed to be visible from outside of the truck. Owners and operators of semi-trailer trucks would find it desirable to provide a fairing assembly that eliminates this gap, thereby improving both the aerodynamic efficiency and the appearance of the vehicle.